In a color photographic light-sensitive material, when it is exposed and thereafter color-developed, the oxidized color-developing agent is reacted with a coupler to form an image.
The color-developing is attained, for instance, by dipping an exposed light-sensitive material in an aqueous alkali solution (a developing solution) in which a color-developing agent is dissolved. This technique have many problems, for example, a problem that the developing solution tends to be deteriorated with the lapse of time and problems concerning treatments of developing solution wastes.
As one effective measure to solve above problems, a method wherein an aromatic primary amine developing agent or its precursor is built in the hydrophilic colloid layer of a light-sensitive material is proposed. Further, a method wherein a sulfonylhydrazine-type developing agent is built in the hydrophilic colloid layer of a light-sensitive material is proposed. Examples of these include methods described, for example, in U.S. Pat. No. 803 783, JP-B-58-14671 ("JP-B" means examined Japanese patent publication), European Patent Nos. 545 491(A1) and 565 165(A1).
However, even these methods cannot attain satisfactory color formation when color-developed; and there is the problem of storage stability.
In the fields of silver halide photographic light-sensitive materials, a so-called color diffusion transfer method in which a diffusible dye is formed imagewise on a light-sensitive material and the image is transferred and fixed to an image-receiving material, to form a color image, is known technique, and many proposals concerned this have been made. Adopted in these methods is a method in which a diffusible dye is generally formed, as a function of developing of silver halide, from a compound (hereinafter called a colorant) produced by modifying a pre-colored image-forming dye (pre-formed dye) to one which is resistant to diffusion. In the method like this, when the colorant is added to the same layer as a silver halide emulsion, an unacceptable reduction in sensitivity to exposure is caused by a filter effect of a dye portion. Hence, generally, in order not to face the problem, a method is adopted in which an image-forming colorant is added to a layer more apart from the exposed surface with respect to the silver halide emulsion layer. In this method, although the above reduction in sensitivity which is caused by the filter effect is avoided, there is an inherent drawback that developing information is transferred from the silver halide emulsion to the colorant inefficiently because the physical distance between the silver halide emulsion and the colorant is large.
In order to improve these drawbacks, a so-called coupling system is proposed in U.S. Pat. No. 4,469,773 and JP-B-63-36487 in which system a dye is formed by a coupling reaction between an oxidized product of a developing agent, which is produced as a function of the developing of silver halide, and a coupler. However, the color-developing agent described therein has a difficulty in the compatibility of the storage stability and the activity of the coupling reaction and a difficulty in modifying both the color-developing agent and the coupler to those having resistance to diffusion.
Novel color-developing agents are proposed in JP-A-09-152702 ("JP-A" means unexamined published Japanese patent application) and JP-A-09-152705. In these methods, however, sufficient color-forming property is not obtained yet. Also, whether or not there are problems concerning the hue and color image stability of a dye to be formed, or the color image stability of a dye to be formed is not mentioned in those publications at all.
Particularly, the compounds described in the said JP-A-9-152705 have the drawbacks that sharpness of a magenta dye to be formed is insufficient and the storage stability of a color image is also insufficient.
In JP-A-9-152702, there is a proposal concerning a heterocyclic hydrazine developing agent having two or more nitrogen atoms. However, in this publication, there is no specific description concerning diffusion transfer type silver halide photographic light-sensitive materials and there is also nothing referring to specific properties (e.g., hue and stability) of a dye to be formed.